How do I go TCPP-free and still hit Class A fire, smoke, and toxicity numbers?

TCPP replacement

Why it matters

TCPP (tris(1-chloro-2-propyl) phosphate) has been the default flame retardant in polyisocyanurate (PIR) boardstock and rigid spray polyurethane foam (SPF) for decades. It is cheap, soluble in the polyol B-side, and works at modest loadings.

It has also become a regulatory liability. ECHA has classified TCPP as a substance of very high concern under the Stockholm Convention review process, and U.S. state legislatures and major real-estate ESG buyers are accelerating bans on chlorinated phosphate flame retardants in building materials. Insurance and combustion-toxicity research has reinforced concerns about HCl evolution and persistent organic pollutants in fire scenarios.

For formulators that means: you need a halogen-free flame retardant that works within your existing line, targets the same fire ratings, and does not upset demold, density, or cell structure. That is the development brief behind Yellow Jacket™ FR — and every programme is confirmed on your formulation before anything is claimed.

How MCPU solves it

Yellow Jacket™ FR uses a phosphorus-rich reactive backbone combined with a char-former package to deliver flame retardancy through condensed-phase chemistry. During combustion the phosphorus moiety drives intumescent char formation while the secondary additives suppress dripping and reduce smoke developed.

Starting loadings in development work generally fall between 8 and 14 phpp (parts per hundred polyol), depending on board density and the ASTM E84 flame-spread target. These are development starting points, not guaranteed performance: the working loading, fire result and process window are established during a formulation review and pilot trial on your own system.

Test data & spec snapshot

Representative values — actual performance depends on your formulation. Pilot data available on request.

Typical applications

• PIR boardstock for commercial roofing and wall insulation
• Closed-cell SPF for residential and commercial buildings
• Rigid foam for cold-storage panels and appliance insulation

Fire, smoke & toxicity (FST)

Why it matters

Building-code FST requirements have tightened in every major jurisdiction. ASTM E84 / UL 723 set the headline Flame Spread and Smoke Developed Index numbers in North America, while CAN/ULC-S102 covers Canadian assemblies and NFPA 286 covers full-scale room-corner tests for some interior finishes.

Smoke and toxicity are not the same as flame spread. A foam can pass FSI < 25 and still produce dangerous smoke loads or HCl-rich combustion products. Buyers — particularly in healthcare, transit, and high-density residential — increasingly ask for both.

How MCPU solves it

Yellow Jacket™ FST pairs the phosphorus-rich FR backbone with a synergist package tuned to suppress smoke developed without adding halogenated co-FRs. In field PIR formulations it has helped customers move from a marginal Class A pass to a comfortable margin while reducing visible smoke production in NBS smoke chamber testing.

Test data & spec snapshot

Representative values — actual performance depends on your formulation. Pilot data available on request.

Typical applications

• PIR roofing where smoke developed is a buyer-spec line item
• Healthcare and transit interior insulation
• Cold-storage panels with strict smoke ratings